I just had the same problem as Olug. The Full screen/window solution worked but I suggest looking into fixing it. I love Creeper World 2, hope I like this one too.
I LLLove this game. Didn't get really hairy till level 47, where I got stuck for a few days. Got my level 50 badge... and now it doesn't go beyond level 51! No levels beyond? A "Congratulations, you've reached the top, no more level-climbing for you" might be appropiate. I still keep playing when I need a little Zen.
 "Creeper World 3: Abraxis"){kind=icon}
 "Idle Evolution"){kind=icon}
 "loops of zen"){kind=icon}